Frequency analyzing method, frequency analyzing apparatus, and spectrum analyzer

a frequency analysis and spectrum analysis technology, applied in the field of frequency analysis methods, frequency analysis apparatus, spectrum analyzers, can solve the problem that the presence of radio waves the frequency of which is spread as in a portable telephone cannot be reliably detected, and achieve good signal-to-noise ratio

Inactive Publication Date: 2005-12-27
ADVANTEST CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0028]In addition, the computation of the correlation value is carried out in accordance with a coherence function, and if the obtained correlation value is greater than a preset fixed value, a decision that a signal exists is rendered and if the obtained correlation value is smaller than the preset fixed value, a decision that a signal does not exist is rendered. Therefore, presence and absence of a signal can be determined without being affected by the strength of the signal to be measured. As a result, the results of frequency analyses having good signal-to-noise ratio can be obtained.

Problems solved by technology

For this reason, there is a serious defect in the prior frequency analyzing method and apparatus that the presence of a radio wave the frequency of which is spread as in a portable telephone cannot be reliably detected.

Method used

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  • Frequency analyzing method, frequency analyzing apparatus, and spectrum analyzer
  • Frequency analyzing method, frequency analyzing apparatus, and spectrum analyzer
  • Frequency analyzing method, frequency analyzing apparatus, and spectrum analyzer

Examples

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first embodiment

[0042]The spectrum analyzer 200 of the first embodiment comprises the frequency analyzing apparatus 100, an arithmetic and logic unit or operation part 23, a second buffer memory 24, and a display 17. In the frequency analyzing apparatus 100 are provided two system's networks each of which comprises a signal extracting device 11, an A / D converter 12, and a frequency analyzing part 13 all of which may have the same constructions as those of the frequency analyzing apparatus 100 shown in FIG. 8. The one network comprises a first signal extracting device 11A, a first A / D converter 12A, and a first frequency analyzing part 13A, and the other network comprises a second signal extracting device 11B, a second A / D converter 12B, and a second frequency analyzing part 13B.

[0043]The frequency analyzing apparatus 100 further comprises: a clock source 14; a first frequency divider or demultiplier 15 that divides the frequency of a clock signal by S; a second frequency divider or demultiplier 15B...

second embodiment

[0066]In the second embodiment, a third buffer memory 25 is provided at the output side of the level decision part 21, and logical “1” or “0” outputted from the level decision part 21 is temporally stored in the third buffer memory 25. Moreover, a frequency bandwidth decision part 26 is provided at the output side of the third buffer memory 25. This frequency bandwidth decision part 26 checks whether logical “1” continues over a predetermined frequency bandwidth or not, and if not, it renders a decision that logical “1” supplied thereto from the third buffer memory 25 is a noise and converts that logical “1” into logical “0” to output it to the arithmetic and logic unit 23. If logical “1” continues over the predetermined frequency bandwidth, the frequency bandwidth decision part 26 renders a decision that it is a signal to be intended to detect and outputs logical “1”s as they are to the arithmetic and logic unit 23. Accordingly, even if an impulse-like noise intermingles with the r...

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Abstract

There are provided frequency analyzing method and apparatus, and a spectrum analyzer capable of reliably detecting and displaying a radio wave even if the radio wave is a frequency spread or low level one. A signal to be measured existing in a frequency band to be measured is extracted by a plurality of measurement signal extracting devices, and each of the extracted plural signals to be measured is frequency analyzed to compute a correlation value with respect to the plural results of frequency analyses. If the computed correlation value is equal to or greater than a preset value, a decision that the signal to be measured exists in the analyzed frequency is rendered, and if the computed correlation value is smaller than the preset value, a decision that the signal to be measured does not exist in the analyzed frequency is rendered. The decision results are displayed.

Description

TECHNICAL FIELD[0001]The present invention relates to a frequency analyzing method that can be suitably used in case of extracting a signal existing in a specified frequency band, and analyzing the frequency of the extracted signal, and a frequency analyzing apparatus using such frequency analyzing method, and to a spectrum analyzer including such frequency analyzing apparatus built therein.BACKGROUND ART[0002]One example of the frequency analyzing apparatus of this kind and one example of the spectrum analyzer including this frequency analyzing apparatus built therein are shown in FIG. 8. Further, in the illustrated examples, a part that detects a signal to be measured and analyzes the frequency of the detected signal will be referred to as “frequency analyzing apparatus” and the whole construction including the frequency analyzing apparatus and a display that displays the result of analysis carried out by the frequency analyzing apparatus will be referred to as “spectrum analyzer”...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): G01R23/16
CPCH04B17/16G01R23/16
Inventor KUROSAWA, MAKOTO
Owner ADVANTEST CORP
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